Friday evening (July 17, 2020) – We drove south (an hour drive) to Powell Observatory for an ASKC members only viewing of Comet Neowise plus Jupiter at opposition and glorious through the 30 inch. Clouds were an issue to our total viewing experience, but it was great to see everyone and it was a surprisingly pleasant evening. We left shortly before eight o’clock and were back home by two minutes to midnight. An excellent excursion and a nice field trip from our lock-down life at home.
My topic for discussion this week will attempt to answer the question:
Why do astronomers believe that the debris that creates many isolated meteors comes from asteroids, whereas the debris that creates meteor showers is related to comets?
But first, I want to share two things that serendipitously fell from my Twitter feed (@mossjon) today. Today’s APOD (Astronomy Picture of the Day@apod) featured the unusual mountain on Ceres (Comins, 2015, p. 239).
The second thing that immediately caught my eye today was an episode of Astronomy Magazine‘s “The Real Reality Show” entitled “How an Asteroid Killed Off the Dinosaurs” covered late in Chapter 8 of our textbook (Comins, 2015, p. 263-4) and which also bonked me on the head via my Twitter feed:
Long answer: Still Jupiter, but let’s dive in and take a more detailed look.
Image Credit: NASA
Birth of a Gas Giant
A long time ago in a solar system very near you, just 1 or 2 AU past the snow line, enough surrounding planetesimals were accreted to become an Earth-like body containing about ten (10) Earth masses of metal and rock. This, in turn, gave this massive body enough gravitational attraction to pull vast amounts of hydrogen, helium and ices near its orbit, creating the first planet in our solar system: Jupiter. Impacts from the infalling gases and ices heated Jupiter up, so much so that for a short time, it outshown the protosun, if viewed from equal distances. Jupiter lacked the total mass to become a star, needing to be seventy-five (75) times more massive to achieve the necessary compression and heat in its core to sustain fusion.
Tomorrow, just after six o’clock in the morning and just as the sun is rising, we’ll experience the first full moon to occur on Christmas Day since 1977. I wasn’t even in high school yet in 1977 (although my husband was already in college by then). If you miss opening this Christmas present, you won’t get another chance until 2034 (by which time I should be retired).
Other astronomical items of note this holiday week include:
On the 4th day of Christmas (Monday that is), Mercury reaches its peak distance from the sun 30 minutes after sunset in the southwest.
On the 5th day of Christmas (Tuesday), Saturn continues its return from behind the Sun. Look to the southeast in the pre-dawn morning time.
On the 6th day of Christmas (Wednesday), look up and south to spy the Seven Sisters (aka as the Pleiades)
On the 8th day of Christmas (Happy New Year!), use binoculars to find Comet Catalina rising close to Arcturus (a very bright star) around midnight and continue to rise high in the southeast until dawn twilight.
On the 9th day of Christmas (Saturday, January 2, 2016) the Earth reaches its closest point to the Sun (at the start of Winter no less)
On the last day of Christmas (Twelfth Night) at 10 p.m. EST, Pluto hides behind the Sun.
Powell Observatory will be open to the public for viewing of Comet Lovejoy from 7:00 PM to 10:00 PM, Friday, January 23rd, 2015. Naked eye, binocular and telescopic views, including the 30″ Ruisinger telescope, of Comet Lovejoy will be the main target of the evening’s viewing, but other astronomical objects will be presented as well. The observatory classroom and bathrooms are heated, but the Ruisinger observatory dome is unheated and all additional telescope and binocular observing will be done outside. It is highly recommended that visitors wear appropriate cold weather clothing.
There are no food or beverage concessions available at the observatory, but visitors may bring their own non-alcoholic beverages and snacks if desired. You can print a map to the observatory clicking here. Visitors with questions about the weather or the evening’s activities should call the observatory at after 6:30 PM on the 23rd.
The ASKC is a non-profit organization. We ask for a suggested donation of $6.00 per adult and $4.00 per child under 12. All donations are used to support and maintain the observatory and the ASKC thanks you for your patronage.
More information on Comet Lovejoy, how to view and how to find it may be found at the following website:
Just as I was settling down and thinking about making my morning cup of tea, I thought I’d check the eastern sky one last time (see my earlier post about cloud cover on the wrong half of the sky). Surprise! The clouds disappeared, probably due to the wind advisory we’re still under. I could barely see the star Spica just breaking through the bare limbs of my neighbor’s trees.
I went back inside and grabbed my binoculars. I then headed to one of my east-facing second floor bedrooms. Thanks to my kids, the window in the south room has no screen so I can open it and have a clear view above my neighbor’s rooftops.
I work up at 4:11 a.m. (Central Time) this morning. It’s a Sunday. Why am I up so early? I have no idea.
Since I was up early, I checked my Sky Safari app on my smartphone to see when Comet Ison would rise. I was in luck. It was scheduled to rise at 4:22, a few minutes before the star Spica.
